Panic handler causes infinite panic recursion

[ttencate]

#0  0x00007d697410dae4 in core::any::{impl#4}::is<&str> (self=..., self=...)
    at /rustc/98aa3624be70462d6a25ed5544333e3df62f4c66/library/core/src/any.rs:200
#1  core::any::{impl#4}::downcast_ref<&str> (self=...)
    at /rustc/98aa3624be70462d6a25ed5544333e3df62f4c66/library/core/src/any.rs:228
#2  core::any::{impl#5}::downcast_ref<&str> (self=...)
    at /rustc/98aa3624be70462d6a25ed5544333e3df62f4c66/library/core/src/any.rs:379
#3  crankstart::panic (panic_info=<optimized out>) at src/lib.rs:297
#4  0x00007d69740ff796 in core::panicking::panic_nounwind_fmt::runtime () at library/core/src/panicking.rs:110
#5  core::panicking::panic_nounwind_fmt () at library/core/src/panicking.rs:122
#6  0x00007d69740ff88a in core::panicking::panic_misaligned_pointer_dereference ()
    at library/core/src/panicking.rs:221
#7  0x00007d697410dc13 in crankstart::abort_with_addr (addr=137891872414744) at src/lib.rs:286
#8  0x00007d697410dbde in crankstart::panic (panic_info=<optimized out>) at src/lib.rs:323
#9  0x00007d69740ff796 in core::panicking::panic_nounwind_fmt::runtime () at library/core/src/panicking.rs:110
#10 core::panicking::panic_nounwind_fmt () at library/core/src/panicking.rs:122
#11 0x00007d69740ff88a in core::panicking::panic_misaligned_pointer_dereference ()
    at library/core/src/panicking.rs:221
#12 0x00007d697410dc13 in crankstart::abort_with_addr (addr=137891872414744) at src/lib.rs:286
#13 0x00007d697410dbde in crankstart::panic (panic_info=<optimized out>) at src/lib.rs:323
#14 0x00007d69740ff796 in core::panicking::panic_nounwind_fmt::runtime () at library/core/src/panicking.rs:110
#15 core::panicking::panic_nounwind_fmt () at library/core/src/panicking.rs:122
#16 0x00007d69740ff88a in core::panicking::panic_misaligned_pointer_dereference ()
    at library/core/src/panicking.rs:221

... and so on, ad infinitum or until the stack overflows with a segmentation fault.

The root cause is abort_with_addr trying to write to a misaligned pointer, 0xdeadbeef.

This can easily be fixed by changing the pointer to *mut u8, because this has size 1, which is guaranteed to be a multiple of the alignment which must therefore also be 1.

(Aside: It would also be nice if the abort could be suppressed with some kind of build flag, because it aborts the simulator before it has a chance to print the panic message.)